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Enhancement by 5-hydroxytryptamine and analogues of desensitization of neuronal and muscle nicotinic receptors expressed in Xenopus oocytes

Enhancement by 5-hydroxytryptamine and analogues of desensitization of neuronal and muscle nicotinic receptors expressed in Xenopus oocytes
Enhancement by 5-hydroxytryptamine and analogues of desensitization of neuronal and muscle nicotinic receptors expressed in Xenopus oocytes
The action of 5-hydroxytryptamine (5-HT) on neuronal and muscle nicotinic acetylcholine receptors (nicotinic AChR) expressed in Xenopus oocytes was studied. 2. 5-HT enhanced the rate of desensitization of the acetylcholine (ACh) current response in all receptor subtypes investigated (muscle, alpha beta 2 gamma delta and alpha 4 beta 2), acting in a dose-dependent manner. 3. 5-HT also reduced the peak current elicited by ACh in a dose-dependent manner. The IC50 value for the muscle type receptor was 227 +/- 0.44 microM, and 166 +/- 0.47 microM and 283 +/- 0.28 microM for the combinations alpha beta 2 gamma delta and alpha 4 beta 2 respectively. 4. The effect of 5-HT on the responses to ACh (10 microM) was found to be independent of membrane voltage over the range tested (-80 to -10 mV), and to be readily reversed by washout. 5. The action of 5-HT could be mimicked by structurally similar molecules. The homologue tryptamine was less potent than 5-HT in blocking the ACh current, with an IC50 of 1.0 +/- 0.02 mM. Ketanserin, a 5-HT2 receptor antagonist, was more potent than 5-HT, the IC50 being 49.0 +/- 1.4 microM. 6. We postulate that a highly conserved portion of the tertiary structure of nicotinic AChRs, which includes some part of the ACh binding site, has affinity for 5-HT and structural analogues.
0007-1188
1636-1640
Cross, K.M.
2d47a27a-b0eb-413f-8e4b-a5b139726f26
Foreman, R.C.
65aa0170-a201-4917-ae82-69b0c9e3933d
Chad, J.E.
d220e55e-3c13-4d1d-ae9a-1cfae8ccfbe1
Cross, K.M.
2d47a27a-b0eb-413f-8e4b-a5b139726f26
Foreman, R.C.
65aa0170-a201-4917-ae82-69b0c9e3933d
Chad, J.E.
d220e55e-3c13-4d1d-ae9a-1cfae8ccfbe1

Cross, K.M., Foreman, R.C. and Chad, J.E. (1995) Enhancement by 5-hydroxytryptamine and analogues of desensitization of neuronal and muscle nicotinic receptors expressed in Xenopus oocytes. British Journal of Pharmacology, 114 (8), 1636-1640.

Record type: Article

Abstract

The action of 5-hydroxytryptamine (5-HT) on neuronal and muscle nicotinic acetylcholine receptors (nicotinic AChR) expressed in Xenopus oocytes was studied. 2. 5-HT enhanced the rate of desensitization of the acetylcholine (ACh) current response in all receptor subtypes investigated (muscle, alpha beta 2 gamma delta and alpha 4 beta 2), acting in a dose-dependent manner. 3. 5-HT also reduced the peak current elicited by ACh in a dose-dependent manner. The IC50 value for the muscle type receptor was 227 +/- 0.44 microM, and 166 +/- 0.47 microM and 283 +/- 0.28 microM for the combinations alpha beta 2 gamma delta and alpha 4 beta 2 respectively. 4. The effect of 5-HT on the responses to ACh (10 microM) was found to be independent of membrane voltage over the range tested (-80 to -10 mV), and to be readily reversed by washout. 5. The action of 5-HT could be mimicked by structurally similar molecules. The homologue tryptamine was less potent than 5-HT in blocking the ACh current, with an IC50 of 1.0 +/- 0.02 mM. Ketanserin, a 5-HT2 receptor antagonist, was more potent than 5-HT, the IC50 being 49.0 +/- 1.4 microM. 6. We postulate that a highly conserved portion of the tertiary structure of nicotinic AChRs, which includes some part of the ACh binding site, has affinity for 5-HT and structural analogues.

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Published date: April 1995

Identifiers

Local EPrints ID: 55930
URI: http://eprints.soton.ac.uk/id/eprint/55930
ISSN: 0007-1188
PURE UUID: 70a135a0-2ae2-4bbd-a2a3-ab8ea0dc3221
ORCID for J.E. Chad: ORCID iD orcid.org/0000-0001-6442-4281

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Date deposited: 06 Aug 2008
Last modified: 12 Dec 2021 02:34

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Contributors

Author: K.M. Cross
Author: R.C. Foreman
Author: J.E. Chad ORCID iD

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